1. Field of the Invention
The present invention relates to a vehicle-mounted navigation system, and more particularly to a navigation system based on a scheme where communications are performed between a vehicle-mounted terminal and a server.
2. Description of the Prior Art
In JP-A-2000-55682, there has been disclosed a navigation system of the following type: A server transfers a map and a guiding route to a vehicle-mounted device, and the vehicle-mounted device performs the navigation using these pieces of information. In this system, at first, the vehicle-mounted device transmits a starting place and a destination place to the server, and the server calculates and determines the guiding route therebetween. After that, the server transfers the route and a map of the route's portion to the vehicle-mounted device, and the vehicle-mounted device performs the route guidance while displaying the map.
In the above-described technology, however, no consideration has been given to a method of controlling the display picture at the time of the route guidance and a reduction in the data transfer amount. Also, no consideration has been given to the operability, e.g., an operation in the case where the vehicle-mounted terminal deviates from the guiding route, or a delivery of the map where the safety during the driving has been taken into account. Moreover, no disclosure has been made concerning a method of grasping a cost needed for the data communications and a charge at the time of downloading the contents.